# Signed vs Unsigned

Learn via video course
FREE
View all courses
DBMS Course - Master the Fundamentals and Advanced Concepts
by Srikanth Varma
1000
5
DBMS Course - Master the Fundamentals and Advanced Concepts
by Srikanth Varma
1000
5
Topics Covered

## Overview

Our number system ranges from minus infinity to plus infinity, with zero in the middle. However, programming has two types of numbers: signed and unsigned. The potential to employ negative numbers is the primary difference between a signed and an unsigned number. Unsigned numbers can only have values that are equal to or greater than zero. On the other hand, signed numbers have a more natural range that covers negative and positive numbers.

## Introduction

The requirement to express numeric values with limited resources drove the creation of signed vs. unsigned numbers. When utilizing 8 bits, there are only 256 possible combinations. Any value between 0 and 255 is considered an unsigned number. On the other hand, having a signed number means you've already lost a bit for representing the sign. With 7 bits, you can only have 128 permutations. Hence an 8-bit signed number's range is -128 to 127. Using unsigned numbers was the way to go if you had limited resources, which was the case in the early days of computers.

Unsigned integers range from 0 to 4,294,967,295 or around 4 billion in 32-bit integers. The signed version ranges from –2,147,483,648 to 2,147,483,647, or around -2 billion to +2 billion. The range is the same, but the values are shifted on the number line.

### Difference between Signed and Unsigned in MySQL

Signed value - Variables with signed numerals can store 0, positive, and negative numbers.
Unsigned value - Variables with unsigned numerals can store only 0 and positive numbers.

### Table of the Range of Values Each Integer Type Can Store Refer

TypeStorage (Bytes)Min signed valueMax signed valueMin unsigned valueMax unsigned value
TINYINT1-1281270255
SMALLINT2-3276832767065535
MEDIUMINT3-83886088388607016777215
INT4-2147483648214748364704924967295
BIGINT8-9,223,372,036,854,775,8089,223,372,036,854,775,807018,446,744,073,709,551,615

### Example

• To specify unsigned id-column

Here, the variable roll_no is of unsigned numeric type. Only 0 and other positive numbers are allowed. It is not capable of storing negative values.

• To specify signed column representing temperature column

Here, the temperature variable is of a signed numeric type. All negative and positive integers and zero can be stored in the temperature variable.

## Conclusion

• An unsigned number contains just zero or positive values, whereas a signed number has both positive and negative numbers along with the value zero.
• The maximum value of signed numbers is half that of unsigned numbers.
• Combining signed and unsigned numbers might cause complications.
• Whether a number is signed or unsigned has no bearing on modern applications.